1. Field of the Invention
The present invention relates to a method for producing N-pyranosyl-tryptophan having a specified structure via organic synthesis. More particularly, the present invention relates to a method for producing N-pyranosyl-tryptophan comprising allowing a pyranose compound having an epoxide group and a protected hydroxyl group to react with a 3-pyrazyl-indole compound and then treating the resulting 1-pyranosyl-3-pyrazyl-indole compound with an acid and a catalyst. Further, the present invention relates to a method for producing an antibody that is specific to N-pyranosyl-tryptophan using N-pyranosyl-tryptophan as a hapten.
2. Description of the Related Art
As a novel modified type of glycoprotein, N-mannosyl tryptophan, in which mannose has been bound to an indole nitrogen atom of tryptophan, was discovered based on a type of peroxidase (Li et al., J. Biol. Chem., 2005, 280, 38513). However, a method for organic synthesis of N-mannosyl tryptophan was not known before now.
Meanwhile, the presence of N-glucosyl-tryptophan has been identified in fruit and Chinese medicine. As a method for producing β-N-glucosyl-tryptophan, a method comprising a step of heating of N-α-acetyl-D-tryptophan and glucose for a long period of time to synthesize the target compound is known (Nyhammer, T. et al., Food. Chem. 1985, 17, 289-296; Gutsche, B. et al., Biochem. J. 1999, 343, 11-19; and C. Unverzagt et al., Tetrahedron Lett. 2004, 45, 295-297). Such method, however, causes a lower yield of β-N-glucosyl-tryptophan synthesized and large amounts of by-products, and thus, makes separation and purification of β-N-glucosyl-tryptophan very difficult. Further, synthesis of a derivative was difficult due to the removal of an acetamide group.